Initial structure for supervisor-mode

The full process hierarchy isn't set up yet, but these changes
help prepare by doing two things:

- Add a -j option to enable supervisor-mode.  Currently, just a single
  "stem" process gets forked early on to be used as the basis for
  further forking into real cluster nodes.

- Separates the parsing of command-line options from their consumption.
  i.e. need to parse whether we're in -j supervisor-mode before
  modifying any global state since that would taint the "stem" process.
  The new intermediate structure containing the parsed options may
  also serve as a way to pass configuration info from "stem" to its
  descendent cluster node processes.

src/Flare.h

@@ -31,8 +31,10 @@ public:
 
 	/**
 	 * Take the object out of the "ready" state.
+	 * @return number of bytes read from the pipe, corresponds to the number
+	 * of times Fire() was called.
 	 */
-	void Extinguish();
+	int Extinguish();
 
 private:
 	Pipe pipe;